Cohort Studies and Databases The Cohorts and Databases Core (CDC) will maintain two cohorts of patients and their associated databases and continually update and add information. In addition, the Core will maintain a database supporting tissue storage and use. The two populations of patients are men and women with breast cancer or women at increased risk because of genetic or histologic risk factors. Tissues are those blood samples and breast specimens kept in repositories at the DFCI, B\VH or MGH. The databases are called CRIS (C'linical Research Information System), REACH (Risk Evaluation And Cancer History), and STIP (Specimen Tracking and Inventory Program). Men and women with breast cancer are prospcctively enteied into CRIS from the Gillette Breast Oncology Clinic at the DFCI and the AVON Breast Evaluation Center at the MGH. Women at high risk for breast cancer arc entered into REACH at the risk evaluation clinics at the DFCI and B1DMC. Data managers at the DFCI and MGH prospectively enter data into both registries. Users in the tissue banks at the DFCI, BWH and MGH use STIP for entry and inventory purposes. Reports are issued by specialized software to requesting investigators and down loaded to other registries. All three databases are kept on Partners HealthCare Information Systems'central computer facilities, and available on workstations throughout the Partners System. The Core will provide reports to SPORE investigators who have approved projects and after consultation about data requirements. The Core is also available to collaborators who are members of the DF/HCC or other investigators on a case-by-case basis. The Core will participate in the Core Coordinating Committee and will abide by policies and procedures agreed upon by the Committee.